Inspection Procedure F-3

INSPECTION PROCEDURE F-3: Sunroof: Sunroof timer function does not work normally.

TECHNICAL DESCRIPTION (COMMENT)
The sunroof motor assembly deactivates the sunroof timer if the SWS communication line is open circuited. In addition, when the doors are opened if the door switch circuit is defective and the timer is on, the sunroof timer should not operate normally.

TROUBLESHOOTING HINTS
- The driver's or passenger's door switch may be defective.
- The sunroof motor assembly may be defective.
- The wiring harness or connectors may have loose, corroded or damaged terminals, or terminals pushed back in the connector.

DIAGNOSIS
Required Special Tools:
- MB991223: Test Harness Set
- MB991502: Scan Tool (MUT-II)
- MB991529: Diagnostic Trouble Code Check Harness

STEP 1. Check method of the in put signal.

Q: Which is to be used, the scan tool or a voltmeter to check the input signal?

Scan tool MB991502: Go to Step 2.

Voltmeter: Go to Step 3.

STEP 2. Check the input signal (by using the scan tool MB991502).
Check the input signals from the following switches:
- Ignition switch (IG1)
- Driver's and passenger's door switch
- Sunroof switch

NOTE: If can be determined whether the wiring harness Between the sunroof motor assembly and the ETACS-ECU is defective or not by checking the SWS communication line.

CAUTION : To prevent damage to scan tool MB991502, always turn the ignition switch to the "LOCK" (OFF) position before connecting or disconnecting scan tool MB991502.




1. Connect scan tool MB991502 to the data link connector.
2. Check that the tone alarm of scan tool MB991502 sounds when the input signal enters.

Q: Does the tone alarm of scan tool MB991502 sound when the input signal enters?

YES : Replace the sunroof motor assembly. The sunroof timer function should work normally.

NO:
- Scan tool MB991502 does not sound when the ignition switch is turned from "ACC" to "ON": Refer to Inspection Procedure O-2 "The ignition switch (IG1) signal is not sent to the ETACS-ECU.
- Scan tool MB991502 does not sound when the driver's or passenger's door is opened: Refer to Inspection :Procedure O-8 "The driver's or passenger's door switch signal is not sent to the ETACS-ECU."
- Scan tool MB9915O2 does not sound when the sunroof switch is turned from "0FF" to "OPEN/TILT UP" or "CLOSE/TILT DOWN": Refer to Inspection Procedure O-19 "The Open/tilt up or close/tilt down switch signal is not sent to the ETACS-ECU.

STEP 3. Check the input signal (by using a voltmeter).
Check the input signals from the following switches:
- Ignition switch (IG1)
- Driver's and passenger's door switch
- Sunroof switch

NOTE: It can be determined whether the wiring harness between the sunroof motor assembly and the ETACS-ECU is defective or not by checking the SWS communication line.




1. Use special tool MB991529 to connect a voltmeter between ground terminal 4 or 5 and ETACS-ECU terminal 9 of the data link connector.
2. Check that the voltmeter indicator deflects once when the input signal enters.

Q: Does the voltmeter indicator deflect?

YES : Replace the sunroof motor assembly. The sunroof timer function should work normally.

NO :
- The voltmeter needle does not fluctuate when the ignition switch is turned from "ACC" to "ON": Refer to Inspection Procedure O-2 "The ignition switch (IG1) signal is not sent to the ETACS-ECU."
- The voltmeter needle does not fluctuate when the driver's or passenger's door is opened: Refer to Inspection Procedure O-8 "The driver's or passenger's door switch signal is not sent to the ETACS-ECU."
- Scan tool MB991502 does not sound when the sunroof switch is turned from "OFF" to "OPEN/ TILT UP" or "CLOSE/TILT DOWN": Refer to Inspection Procedure O-19 "The open/tilt up or close/tilt down switch signal is not sent to the ETACS-ECU."